JP7498704B2 - Connection element, part and connection method thereof - Google Patents

Description

The present invention relates to a connection element as specified in the preamble of claim 1, a method for producing a component connection as specified in the preamble of claim 12 and a component connection as specified in the preamble of claim 21.

Connection elements used to connect two superimposed component layers are known in the prior art. These connection elements are also known as semi-tubular self-piercing rivets. US Pat. No. 5,399,433 discloses a semi-tubular self-piercing rivet that is rotationally driven, the rotation of which heats the contact area between the rivet and the base layer, facilitating the rivet to penetrate the base layer. Furthermore, a retaining structure is provided in the hollow space of the connection element to prevent axial loosening of the slug held in the rivet.

US Patent Application Publication No. 2016/0332215

The object of the present invention is to provide a connection element for producing component connections that enhances the shear strength of the overlapping component layers.

In a manner known per se, the connecting element comprises a shaft and a drive capable of driving said shaft in rotation in one direction, said hollow cylindrical shaft having at least one free end and said drive being arranged opposite said free end. A hollow space is formed in said hollow cylindrical shaft.

According to the invention, driver structures acting in the circumferential direction of the hollow cylindrical shaft are arranged in the hollow space. On the side, these driver structures extend linearly parallel to the element axis or with an angular deviation of less than 20° relative to the element axis projected on the side, and/or the driver structures are arranged at the drive end.

The driver structure is used to cut a piece of slug from the top layer of the component connection by a hollow cylindrical shaft and rotate the slug together with the shaft. This allows the slug to be welded to the base layer as it is rotated together with the connection element. The slug welded to the base layer extends into the top layer, creating a clear connection in the shear direction. This significantly increases the shear strength between the base and top layers.

Preferably, the connecting element has a shoulder that is connected to the shaft. This creates a secure connection along the longitudinal axis of the connecting element between the top layer and the shoulder in addition to the previously mentioned secure connection. This creates a strong connection between the two parts not only laterally but also longitudinally, especially when the shaft is flared at the base layer during the riveting process after slug welding.

In a first embodiment, the shoulder can be part of the head that closes the shaft. This is a simple design that resembles a particularly rotatable semi-tubular self-piercing rivet.

Alternatively, the shoulder can be designed in the form of an annular shoulder with a central recess whose smallest diameter corresponds at least to the inner diameter of the hollow cylindrical shaft. As a result, a reliable connection can be created between the annular collar and the top layer while allowing the slug material to pass upwards into the hollow cylindrical shaft. The material that rises therein can then be reused to form the head. Thus, generally speaking, the amount of material entering the part connection is less, resulting in a lower overall installation height.

The central recess is preferably designed such that its diameter increases in the direction away from the free end of the shaft. This creates a larger volume to accommodate the slug material and therefore creates a shoulder in a geometry that can be more easily pushed in the direction of the top layer when an axial force is applied.

Preferably, the drive is formed in the head and/or shoulder. This allows for particularly efficient transmission of rotational movements.

According to another preferred embodiment, the driver structure located at the drive end is formed on the underside of the head.

In a particularly advantageous manner, the driver structures which run laterally in a straight line parallel to the central axis of the element or with an angular deviation of 20° to the central axis of the element projected on the side are of raised design. This has the advantage that the raised structures are easier to press into the walls of the slug, thus ensuring reliable rotational synchronization of the slug. If a driver structure of raised design is viewed in cross section, the flats further radially inwards are of smaller area than the flats further radially outwards.

In addition to or instead of raised driver structures, the driver structures can be designed in the form of grooves that extend laterally in a straight line parallel to the central axis of the element or with an angular deviation of 20° relative to the central axis of the element projected on the side.

According to another preferred embodiment, the free end can be provided with a cutting edge, in particular in the form of a chamfer, which on the one hand facilitates the cutting out of the slug from the top layer and on the other hand facilitates the penetration of the connecting element into the base layer, where the free end is subjected to a deformation process in order to be flared.

In particular, the connection elements are made of a ferrous metal, especially steel.

The overall length of the connecting element according to the present invention is preferably less than 2.5 times the outer diameter of the hollow cylindrical shaft, and more preferably less than 10 mm.

According to yet another aspect of the invention, it relates to a method for producing a component connection between two component layers, including a base layer and a top layer disposed thereon, in which an axial force acts on a connection element having a hollow cylindrical shaft to rotate the element and drive it into the top layer. The interior of the shaft cuts a slug from the top layer, which is entrained within the connection element as it rotates. A downward force acts on the slug as it rotates, welding it to the base layer, after which at least a portion of the connection element is pressed into the base layer.

Preferably, the speed at which the connecting element is driven until the slug is welded is at least 2000 rpm.

For this purpose, the connecting element can have a semi-hollow or hollow shaft, with or without a driver structure.

In a further development of the production method according to the invention, at least a first step can be included in which the connecting element is placed on the shaft, in particular at high speeds of more than 5000 rpm and in particular with an axial force of less than 3 kN. This ensures that deformation of the connecting element is prevented when the slug is cut off until the connecting element reaches the surface of the base layer.

According to the invention, a second step can be further carried out in which the cut slug is welded to the base layer by applying an axial downward force to the slug as it continues to rotate, while at the same time increasing the axial force applied by the tool compared to the initial force. This force is preferably greater than 6 kN. The speed can be the same as in the first stage or can be reduced to significantly prevent slippage between the slug and the lower part layer.

The second step can be initiated once the connection element, starting from the initial position, passes axially through the thickness of the top layer.

The pressing force can be applied to a connecting element having a head that closes a hollow cylindrical shaft opposite its drive direction, from where this force is applied to the slug via the head of the connecting element.

According to the invention, the connection element is furthermore open towards the drive direction at least above the hollow space of the hollow cylindrical shaft, and the pressing force is applied directly to the slug by a setting tool which applies the pressing force to the connection element.

Furthermore, according to the invention, a third step can be carried out. The third step can be carried out following the second step or immediately after the first step. In this step, the connection element and the slug are subjected to an axial force, in particular of more than 8 kN, which is increased compared to the frictional axial force of the second step and the speed is decelerated, in particular to zero. This allows a reliable axial connection of the connection element to the base layer and/or to the top layer. Preferably, the second step is completed and the third step is started just before the head comes into contact with the top board, in particular when the underside of the head is spaced 1/10 mm to 5/10 mm from the top layer. Thus, based on the known thickness of the component layer and the dimensions of the connection element, the relative movement distance can be calculated in advance. The third stage is completed after a certain period, which is preferably between 0.1 and 0.5 seconds.

Particularly in the first and second steps, the axial force and speed are adjusted with the aim of keeping them as constant as possible. Similar adjustments are performed in the third step. With this approach, the connecting element penetrates the part connection under axial force and rotation.

If the connecting element is open at least above the hollow space of the hollow cylindrical shaft in the insertion direction and contact pressure is applied directly to the slug by a setting tool which applies contact pressure to the connecting element, the slug is made to flare at the end opposite the insertion direction. In this way, a reliable connection can be created between the slug and the top layer. In this case, the slug can be reliably connected to the top layer either indirectly, i.e. via the connecting element, or directly.

The method according to the invention is preferably used to produce component connections comprising at least one layer of a magnesium alloy and/or at least one layer of an aluminum alloy, in particular Al5xxx, Al6xxx or Al7xxx. For this purpose, in a first step, a speed of about 8000 rpm is set with an axial force of about 2 kN, and in a second step, a speed of about 5000 rpm with an axial force of about 8 kN. In a third step, the axial force is adjusted to about 9 kN and the speed is adjusted to zero. In this arrangement, the connection element is preferably steel. "About" in this context means a deviation of plus or minus 20%.

The invention further relates to a component connection comprising a base layer and at least one top layer arranged thereon, a hollow cylindrical shaft and a connecting element having a drive capable of driving the shaft in a rotational direction. The hollow cylindrical shaft has a free end and the drive is arranged at an end of the shaft opposite the free end. A hollow space is formed by the hollow cylindrical shaft.

The portion of the hollow cylindrical shaft at the free end of the shaft is completely surrounded by the base layer, and the interior of the hollow cylindrical shaft contains the slug cut from the top layer.

In the hollow space of the connection element, there is a material connection between the base layer and the slug.

Preferably, a driver structure acting in the circumferential direction of the hollow cylindrical shaft is disposed in the hollow space, the driver structure is surrounded by the material of the slug, and further, there is a material connection between the base layer and the slug.

Preferably, the component connection may include an axially acting secure connection created by molding radially displaced material of a slug that protrudes axially beyond the top layer into a collar that provides a secure connection to the top layer and/or the connecting element.

According to another advantageous embodiment, a secure connection acting in the axial direction can be achieved by a secure fit of the connection elements with the top layer and a secure fit of the connection elements of the base layer.

In particular, a secure connection to the base layer is achieved by flaring the free end of the connection element facing the insertion direction.

The connecting element has a higher strength than the base and top layers. This ensures that the slug can be cut through the top layer and the connecting element can penetrate the base layer.

In principle, the base layer and the top layer can be made of non-ferrous metal, and the connecting elements can be made of steel or non-ferrous metal.

Alternatively, the base layer and the top layer, or only the top layer, can be made of a thermoplastic material and the connecting elements can be made of a plastic material, steel or a non-ferrous metal.

In a particularly advantageous embodiment, the connection elements of the component connections are of the above-described design.

Further advantages, features and possible applications of the present invention can be gleaned from the following description with reference to the embodiments shown in the drawings.

FIG. 1 is a side view of a connecting element according to the present invention. FIG. 1A is a cross-sectional view of a connecting element according to the present invention seen in FIG. FIG. 1B is a cross-sectional view across the shaft of the connecting element of FIG. FIG. 2 shows a perspective view from above of the connecting element of FIG. 1 with a collar. FIG. 3 is a side view of another embodiment of a connecting element according to the present invention. FIG. 3A is a cross-sectional view of the connecting element seen in FIG. 3B is a cross-sectional view taken across the shaft of the connecting element of FIG. 3. FIG. FIG. 4 is a side view of another connecting element according to the present invention. FIG. 4A is a cross-sectional view of the connecting element seen in FIG. FIG. 4B is a cross-sectional view across the connecting element of FIG. FIG. 5A is a diagram of a first step in the production of a component connection using the connection element according to the invention shown in FIG. FIG. 5B is a diagram of a second step in the production of a component connection using the connection element according to the invention shown in FIG. FIG. 5C is a diagram of a third step in the production of a component connection using the connection element according to the invention shown in FIG. FIG. 6A is a diagram of a first step in the production of a component connection using the connection element according to the invention shown in FIG. FIG. 6B is a diagram of a second step in the production of a component connection using the connection element according to the invention shown in FIG. FIG. 6C is a diagram of a third step in the production of a component connection using the connection element according to the invention shown in FIG.

The side view of FIG. 1 shows a connecting element 10 according to the invention for connecting a base layer to a top layer arranged thereon. The connecting element 10 comprises a hollow cylindrical shaft 12 having a free end 14 and a drive 16 provided at the end opposite the free end 14. The drive 16 is designed as an external drive and has a corresponding positive locking structure. The connecting element 10 will be described in more detail with reference to the following figures:

Figure 1A is a cross-sectional view of a connecting element 10. Shown in this figure is a hollow cylindrical shaft 12 and a collar 18 with a drive 16 formed thereon. The hollow cylindrical shaft 12 has ribs 22 on its inner side surface 20, which in this example extend the entire length of the hollow cylindrical shaft 12. The ribs 22 of the connecting element 10 function to entrain slugs removed from the top layer during the rotating motion of the connecting element 10. By entraining the slug in the rotating motion of the connecting element, the slug can be integrally bonded to the base layer in a friction welding process.

The free end 14 of the hollow cylindrical shaft 12 is provided with a chamfer 26 to facilitate penetration of the top layer and, if necessary, to allow the hollow cylindrical shaft 12 to be flared during the deformation process of the base layer.

This figure also shows ribs 22 that extend parallel to the element central axis M of the connection element 10.

Figure 1B is a cross-sectional view taken along line B-B through the shaft 12 of the connecting element 10. As can be seen in this figure, this embodiment has three ribs 22 on the side surface 20. These ribs 22 act to entrain the slug punched from the top layer in the rotational movement of the connecting element, so that a welded joint is made between the slug and the front base layer.

Figure 1A clearly shows that the connecting element 10 is completely hollow. The collar 18 therefore extends around an opening 24 that flares axially in a direction opposite the free end 14 of the shaft 12. In this way, material removed from the top layer passes through the connecting element 10 in the connecting process, thus creating a secure fit between the connecting element and the slug.

Figure 2 is a perspective view of the connecting element 10 shown in Figure 1. Particularly clearly visible in Figure 2 is the opening 24 in the center of the connecting element 10. This opening 24 is completely filled during the connecting process, thus ensuring a tight connection. The opening 24 has proven to be particularly advantageous for connections where a secure connection is not established between the connecting element and the base layer.

The method for producing the component connections will now be described in more detail with reference to Figures 5a-5c.

Figures 3, 3A and 3B show another embodiment of a connecting element 30 according to the invention. Figure 3A shows a cross-section of the connecting element 30 along line A-A in Figure 1. This connecting element 30 substantially corresponds to the connecting element 10 described with reference to Figure 1. The embodiment of Figure 3 differs from that of Figure 1 in that in this case the driver structures are not in the form of ribs 22 but in the form of grooves 32. This can be seen particularly well in the cross-section of the shaft along line B-B (Figure 3B).

Figure 4 shows another embodiment of the connecting element 40, which has a shaft 42 as in Figure 1, but the drive 48 is located not on the collar 44 but on the head 46 on which the collar 44 is provided. In this embodiment, the head 46 forms the end of the hollow cylindrical shaft 42 at its head end, as shown in the cross-sectional view of the connecting element 40 taken along line A-A in Figure 4A. In this embodiment, the material cut from the top layer cannot escape from the connecting element. In this embodiment, the force acting on the slug is applied via the head 46.

Figure 4B is a perspective view of the connecting element 40 showing the closed surface of its head 46.

5A-5C are diagrams illustrating the production steps of a method for producing a connection between a base layer 52, a top layer 54, and a connecting element 58 according to the present invention that is entirely hollow, as shown, for example, in FIG. 1.

The base layer 52 and the top layer 54 are held between the anvil 56 and the setting unit.

The setting unit comprises a drive tool 60 adapted to drive the connecting element 58 in rotation. At the same time, the drive tool exerts an axial contact pressure on the connecting element 58 in the drive direction. The drive tool 60 has a central bulge 61, in particular of a conical shape, which, when it comes into contact with the connecting element 58, protrudes into the hollow space of the connecting element 58. This serves to position the connecting element 58 on the top layer 54.

Figure 5B is a diagram of a process for the production of a component connection according to the invention, in which a connecting element 58 cuts a slug 62 from the top layer 54 under rotation and contact pressure, which slug is received in the hollow space. The slug is rotated by a driver structure 64 located in the hollow space and forms a friction welded joint with the material of the base layer 52 under contact pressure and rotation.

Figure 5C shows the material of the slug 62 rising as the connecting element penetrates further into the base layer 52. The material rises to the drive tool 60 where it is laterally displaced by the bulge 61 of the drive tool. As a result, the slug 62 creates a secure connection via the connecting element 58, which is conically recessed at its head end. In this way, a reliable connection is made between the top layer 54 and the base layer 52 via the connecting element 58 and the slug 62.

6A-6C show a further embodiment of a method for producing a component connection, which is similar to the one described with reference to FIGS. 5A-5C. The component connection comprises a base layer 72, a top layer 74 arranged thereon, and a connecting element 78 according to the invention, which is particularly shown in FIG. 4. The connecting element 78 has a head 80 provided with a drive, which forms the end of the hollow shaft 76 of the connecting element 78. The base layer 72 and the top layer 74 are preferably made of aluminum, whereas the connecting element 78 is made of steel. As mentioned above, the connecting element 78 is driven into the top layer 74 in a first cutting step, preferably at a speed of more than 2000 rpm and with a contact pressure preferably less than 3 kN. Thus, a slug 82 is cut out of the material of the top layer 74 and is caught in the rotating movement of the connecting element 78 by a driver structure formed on the inside of the side surface, preferably taking the form of a rib extending parallel to the element central axis M, and is then welded to the top layer 74 via its front surface. The welding is preferably performed with a higher contact pressure than that used in the previous cutting stage. The contact pressure applied by the drive tool (not shown here) is transferred to the slug 82 through the head of the connecting element. Furthermore, FIG. 5C shows a complete connection with a material connection formed between the base layer 72 and the slug 82, in which the connecting element 78 is deformed by the anvil 84 to penetrate through the base layer 72 and the end of the shaft 76 located in the base layer 72 is deformed to flare outward, as in the case of a riveted connection, thus establishing a conformal connection in the set direction between the base layer 72 and the top layer 74. The riveting process is carried out using a particularly increased contact pressure.

Thus, the slugs 78 connected to the base layer 72 by friction welding provide a connection with improved load-bearing capacity in the direction of shear, i.e., transverse to the set direction.

Claims (25)

1. A connection element (10, 30, 40, 58, 78) for connecting a part of a base layer (52, 72) to a part of a top layer (54, 74) arranged thereon, comprising a hollow cylindrical shaft (12, 42, 76) and a drive (16) capable of driving said shaft (12, 42, 76) in rotation in one direction, said hollow cylindrical shaft (12, 42, 76) having at least one free end, said drive (16, 48) being arranged opposite said free end, and a hollow space being formed in said hollow cylindrical shaft (12, 42, 76),
A driver structure (22, 32) acting in a circumferential direction of the hollow cylindrical shaft (12) is disposed in the hollow space;
the driver structure is arranged to extend linearly on the side surface (20) in a set direction parallel to the element central axis (M) or with an angular deviation of maximum 20° with respect to the element central axis (M) projected on the side surface (20) and/or is arranged at the drive end,
the driver structure (22, 32) for rotating with the shaft (12) a slug cut from the top layer (54, 74) by the shaft (12);
a shoulder (18, 44) connected to said shaft (12, 42, 76);
said shoulder (18) being designed as an annular shoulder (18) having a central recess (24) whose smallest diameter corresponds at least to the inner diameter of the hollow cylindrical shaft (12);
A connecting element, characterized in that said central recess (24) is designed such that its diameter increases in the direction away from said free end of said shaft (12). 2. The connecting element according to claim 1,
A connecting element, characterized in that said shoulder (18, 44) is part of a head (46) forming the end of said shaft. A connecting element according to claim 1 or 2,
A connecting element, characterized in that said drive (16, 48) is formed in the head (46) and/or in said shoulder (18). A connecting element according to any one of claims 1 to 3,
A connecting element, characterized in that the driver structure located at the drive end is formed on the underside of a head (46) . A connecting element according to any one of claims 1 to 4 ,
A connecting element, characterized in that the driver structure extending linearly on the side surface parallel to the element central axis or linearly on the side surface with an angular deviation of 20° relative to the element central axis projected on the side surface is provided in the form of a raised portion (22). A connecting element according to any one of claims 1 to 5 ,
A connecting element, characterized in that the driver structure extending linearly on the side surface parallel to the element central axis or linearly on the side surface with an angular deviation of 20° relative to the element central axis projected onto the side surface is provided in the form of a groove (32). A connecting element according to any one of claims 1 to 6 ,
A connecting element, characterized in that it is provided at said free end with a cutting edge, in particular in the form of a chamfer (26). A connecting element according to any one of claims 1 to 7 ,
A connecting element, characterized in that it is made of a ferrous metal, in particular steel. A method for connecting parts, comprising connecting two part layers (52, 54, 72, 74) including a base layer (52, 72) and a top layer (54, 74) disposed thereon, with a connecting element (10, 30, 40, 58, 78) having a hollow cylindrical shaft (12, 42, 76), comprising:
A connecting element (10, 30, 40, 58, 78) is driven into the top layer (54, 74) under rotation and axial force;
a slug (62, 82) is cut from the top layer (54, 74) by the interior of the shaft and entrained by the rotation of the connecting element;
Under rotational and contact pressure, the slug (62, 82) is welded to the base layer (52, 72);
A method for connecting components, characterized in that at least a portion of the connecting element (10, 30, 40, 58, 78) is pressed into the base layer (52, 72). 10. The method for connecting components according to claim 9,
10. A method for connecting parts, comprising the step of: driving said connecting element (10, 30, 40, 58, 78) until said slug (62, 82) is welded in place at a speed of at least 2000 rpm. The method for connecting components according to claim 10,
1. A method for connecting parts, comprising the steps of: performing a first step in which the connecting element (10, 30, 40, 58, 78) is applied at a suitable speed and axial force for cutting so as to ensure that the connecting element (10, 30, 40, 58, 78) is prevented from being deformed when the slug (62, 82) is cut until the connecting element (10, 30, 40, 58, 78) reaches the surface of the base layer (52, 72). The method for connecting parts according to claim 11,
a second step is performed in which the cut-out slug (62, 82) is welded to the base layer (52, 72) by applying an axial force to the slug (62, 82) for welding while continuing to rotate the slug (62, 82);
11. A method of joining parts, characterized in that the axial force applied by the tool for welding is increased compared to the axial force applied for cutting. The method for connecting parts according to claim 12,
said connecting element (10, 30, 40, 58, 78) has a head which closes said hollow cylindrical shaft (12, 42, 76) at the end opposite to its insertion direction;
10. A method of connecting parts, comprising the steps of: applying an axial force for welding to the slug (62, 82) at the head of the connecting element. The method for connecting parts according to claim 12,
the connecting element (10, 30, 40, 58, 78) is open relative to the insertion direction at least above the inner surface of the hollow cylindrical shaft (12, 42, 76);
13. A method of connecting parts, comprising the steps of: applying said contact pressure to said slug (62, 82) by a setting tool that applies said contact pressure to said connecting element (10, 30, 40, 58, 78). The method for connecting parts according to any one of claims 12 to 14,
A third step is performed in which the axial force acting on the connection element (10, 30, 40, 58, 78) and the slug (62, 82) is increased and the speed is reduced compared to the axial force in the second step in order to create a secure connection in the axial direction to the base layer (52, 72) and/or the top layer (54, 74).
A method for connecting parts. 16. The method for connecting components according to claim 15,
the connecting element (10, 30, 40, 58, 78) is open relative to the insertion direction at least above the inner surface of the hollow cylindrical shaft (12, 42, 76);
the contact pressure is applied to the slug (62, 82) by a setting tool that applies the contact pressure to the connecting element (10, 30, 40, 58, 78);
2. A method for connecting parts, comprising the steps of: connecting the slugs (62, 82) such that the ends of the slugs (62, 82) located opposite each other in the insertion direction are flared. A part connected by the connecting element (10, 30, 40, 58, 78) comprising a base layer (52, 72) and at least one top layer (54, 74) arranged thereon, a hollow cylindrical shaft (12, 42, 76) and a drive arranged at an end opposite to the free end, the hollow cylindrical shaft (12, 42, 76) forming a hollow space, a part of the hollow cylindrical shaft (12, 42, 76) being completely surrounded by the base layer (52, 72), and a slug (61, 82) being cut out of the top layer (54, 74) by the interior of the hollow cylindrical shaft (12, 42, 76),
Component, characterized in that in the hollow space there is a material connection between the base layer and the slug (61, 82). 18. The component of claim 17,
a driver structure acting in a circumferential direction of the hollow cylindrical shaft is disposed in the hollow space;
The component, wherein the driver structure is surrounded by material of the slug. 19. The part according to claim 17 or 18,
A component, characterized in that an axially acting secure connection is created by the radially displaced material of the slug (62, 82) protruding from the top layer (54, 74) forming a collar on the top layer (54, 74) and/or on the connecting element (10, 30, 40, 58, 78). 19. The part according to claim 17 or 18,
A part, characterized in that a positive connection acting in the axial direction is produced by a positive fit of the connecting elements (10, 30, 40, 58, 78) with the top layer (54, 74) and a positive fit of the connecting elements (10, 30, 40, 58, 78) of the base layer. 21. The component according to any one of claims 17 to 20,
A component, characterized in that a secure connection with the base layer (52, 72) is produced by flaring the free ends of the connecting elements (10, 30, 40, 58, 78) extending in the insertion direction. 22. The component according to any one of claims 17 to 21,
The component, wherein the connecting element (10, 30, 40, 58, 78) has a strength greater than that of the base layer (52, 72) and the top layer (54, 74). 23. The component according to any one of claims 17 to 22,
Component, characterized in that said base layer and said top layer (54, 74) are made of a non-ferrous metal and said connecting elements are made of steel or a non-ferrous metal. 23. The component according to any one of claims 17 to 22,
Component, characterized in that said base layer and said top layer (54, 74) are made of a thermoplastic material and said connecting elements are made of a plastic material, steel or a non-ferrous metal. 25. The component according to any one of claims 17 to 24,
9. A component, characterized in that the connecting element is of the type described in any one of claims 1 to 8.

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